These streams of hot water, narrow at first, some twenty leagues in breadth, long preserve their force and their identity, but by degrees they grow weaker as they widen ultimately to about a thousand leagues. Maury estimates that the hot water stream which flows from the Antilles in a northernly course towards us displaces and modifies a fourth part of the waters of the Atlantic. These great features in the life of the seas, noticed only recently, were, however, as visible as the continents themselves. Our great Atlantic and her sister, the Indian artery, proclaim themselves by their color. In each case it is a great blue torrent which traverses the green waters; so darkly blue is this torrent, that the Japanese call theirs the _black river_. Ours is very clearly seen, as it leaps boilingly from the Gulf of Mexico, between Cuba and Florida, and flows west, salt, and distinguishable between its two green walls. In vain does the Ocean press upon it, on either side, it still flows on, unbroken. By I know not what intrinsic density, or molecular attraction, these blue waters are so firmly held together, that, rather than admit the green water, they rear their centre into an arch, and they thus slope to the right and to the left, so that anything thrown into them rolls off into the ocean. Rapid and strong, this Gulf stream at first flows towards the north, along the shores of the United States; but, on reaching the great bank of Newfoundland, its right arm sweeps off to the eastward, while the left arm, as an under current, hastens to create, towards the Pole, the recently discovered open sea where all else around is fast frozen. The right arm spreading out, and proportionately weakened, at length reaches Europe, touches Ireland and England, which again divide the waters previously divided at Newfoundland. Weaker and weaker, it yet carries a little warmth to Norway, and carries American woods to that poor Iceland which, but for them, would die frozen beneath the very fires of her volcano.